/* XMLException.java                                               NanoXML/Java
 *
 * $Revision: 1.4 $
 * $Date: 2002/01/04 21:03:29 $
 * $Name: RELEASE_2_2_1 $
 *
 * This file is part of NanoXML 2 for Java.
 * Copyright (C) 2000-2002 Marc De Scheemaecker, All Rights Reserved.
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from the
 * use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 *  1. The origin of this software must not be misrepresented; you must not
 *     claim that you wrote the original software. If you use this software in
 *     a product, an acknowledgment in the product documentation would be
 *     appreciated but is not required.
 *
 *  2. Altered source versions must be plainly marked as such, and must not be
 *     misrepresented as being the original software.
 *
 *  3. This notice may not be removed or altered from any source distribution.
 */

package net.n3.nanoxml;

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * An XMLException is thrown when an exception occurred while processing the XML
 * data.
 * 
 * @author Marc De Scheemaecker
 * @version $Name: RELEASE_2_2_1 $, $Revision: 1.4 $
 */
public class XMLException extends Exception {

	/**
	 * The message of the exception.
	 */
	private String msg;

	/**
	 * The system ID of the XML data where the exception occurred.
	 */
	private String systemID;

	/**
	 * The line number in the XML data where the exception occurred.
	 */
	private int lineNr;

	/**
	 * Encapsulated exception.
	 */
	private Exception encapsulatedException;

	/**
	 * Creates a new exception.
	 * 
	 * @param msg
	 *            the message of the exception.
	 */
	public XMLException(String msg) {
		this(null, -1, null, msg, false);
	}

	/**
	 * Creates a new exception.
	 * 
	 * @param e
	 *            the encapsulated exception.
	 */
	public XMLException(Exception e) {
		this(null, -1, e, "Nested Exception", false);
	}

	/**
	 * Creates a new exception.
	 * 
	 * @param systemID
	 *            the system ID of the XML data where the exception occurred
	 * @param lineNr
	 *            the line number in the XML data where the exception occurred.
	 * @param e
	 *            the encapsulated exception.
	 */
	public XMLException(String systemID, int lineNr, Exception e) {
		this(systemID, lineNr, e, "Nested Exception", true);
	}

	/**
	 * Creates a new exception.
	 * 
	 * @param systemID
	 *            the system ID of the XML data where the exception occurred
	 * @param lineNr
	 *            the line number in the XML data where the exception occurred.
	 * @param msg
	 *            the message of the exception.
	 */
	public XMLException(String systemID, int lineNr, String msg) {
		this(systemID, lineNr, null, msg, true);
	}

	/**
	 * Creates a new exception.
	 * 
	 * @param systemID
	 *            the system ID from where the data came
	 * @param lineNr
	 *            the line number in the XML data where the exception occurred.
	 * @param e
	 *            the encapsulated exception.
	 * @param msg
	 *            the message of the exception.
	 * @param reportParams
	 *            true if the systemID, lineNr and e params need to be appended
	 *            to the message
	 */
	public XMLException(String systemID, int lineNr, Exception e, String msg, boolean reportParams) {
		super(XMLException.buildMessage(systemID, lineNr, e, msg, reportParams));
		this.systemID = systemID;
		this.lineNr = lineNr;
		this.encapsulatedException = e;
		this.msg = XMLException.buildMessage(systemID, lineNr, e, msg, reportParams);
	}

	/**
	 * Builds the exception message
	 * 
	 * @param systemID
	 *            the system ID from where the data came
	 * @param lineNr
	 *            the line number in the XML data where the exception occurred.
	 * @param e
	 *            the encapsulated exception.
	 * @param msg
	 *            the message of the exception.
	 * @param reportParams
	 *            true if the systemID, lineNr and e params need to be appended
	 *            to the message
	 */
	private static String buildMessage(String systemID, int lineNr, Exception e, String msg, boolean reportParams) {
		String str = msg;

		if (reportParams) {
			if (systemID != null) {
				str += ", SystemID='" + systemID + "'";
			}

			if (lineNr >= 0) {
				str += ", Line=" + lineNr;
			}

			if (e != null) {
				str += ", Exception: " + e;
			}
		}

		return str;
	}

	/**
	 * Cleans up the object when it's destroyed.
	 */
	protected void finalize() throws Throwable {
		this.systemID = null;
		this.encapsulatedException = null;
		super.finalize();
	}

	/**
	 * Returns the system ID of the XML data where the exception occurred. If
	 * there is no system ID known, null is returned.
	 */
	public String getSystemID() {
		return this.systemID;
	}

	/**
	 * Returns the line number in the XML data where the exception occurred. If
	 * there is no line number known, -1 is returned.
	 */
	public int getLineNr() {
		return this.lineNr;
	}

	/**
	 * Returns the encapsulated exception, or null if no exception is
	 * encapsulated.
	 */
	public Exception getException() {
		return this.encapsulatedException;
	}

	/**
	 * Dumps the exception stack to a print writer.
	 * 
	 * @param writer
	 *            the print writer
	 */
	public void printStackTrace(PrintWriter writer) {
		super.printStackTrace(writer);

		if (this.encapsulatedException != null) {
			writer.println("*** Nested Exception:");
			this.encapsulatedException.printStackTrace(writer);
		}
	}

	/**
	 * Dumps the exception stack to an output stream.
	 * 
	 * @param stream
	 *            the output stream
	 */
	public void printStackTrace(PrintStream stream) {
		super.printStackTrace(stream);

		if (this.encapsulatedException != null) {
			stream.println("*** Nested Exception:");
			this.encapsulatedException.printStackTrace(stream);
		}
	}

	/**
	 * Dumps the exception stack to System.err.
	 */
	public void printStackTrace() {
		super.printStackTrace();

		if (this.encapsulatedException != null) {
			System.err.println("*** Nested Exception:");
			this.encapsulatedException.printStackTrace();
		}
	}

	/**
	 * Returns a string representation of the exception.
	 */
	public String toString() {
		return this.msg;
	}

}
